1. Field of the Invention
The present invention relates to the field of container handling apparatus, and more particularly to the field of apparatus for individually handling containers as may be used in container uncasing apparatus.
2. Prior Art
Various types of container handling apparatus are well known in the prior art. Such apparatus includes equipment for handling containers individually and for handling containers in bulk. (Most common of this latter type are conveyor systems which generally transport a continuous stream of containers which are generally unsynchronized with respect to the conveyor system, except as may be accomplished at the entry to a particular piece of equipment fed by the conveyor, or as may naturally result from the delivery of containers to the conveyor by equipment individually handling the containers.)
Equipment for individually handling containers generally has certain physical constraints within which it must operate. In particular, containers are commonly encountered by such equipment supported from the bottom thereof, whether on a conveyor or in cases from which they are to be removed. If located on a conveyor, reasonable access to both the sides and the top of the containers is generally available, so that grippers for individually receiving containers from a conveyor system may engage the containers from the side or top (or both) depending upon the purposes for which they are to be individually handled and the preference of the equipment designer. In certain situations, however, side access to containers is not available, and access from above has certain inherent physical constraints limiting the nature of the grippers which might be considered for use.
The most notable of the foregoing limitations is encountered in uncasers, that is, equipment for removing empty containers from cases or cartons in which they are received and delivering the containers to a container filling system. It is common practice for containers for certain products to be shipped to the product manufacturer by the container manufacturer in cardboard boxes having the top flaps folded but not sealed. These boxes are marked with the appropriate marking of the product manufacturer (not the container manufacturer) so that the product manufacturer may remove the containers, fill the containers with its product and replace the containers in the boxes for sealing and shipment. In this manner boxes are essentially reused so as to provide maximum convenience in handling both the empty containers and the filled containers. However, equipment is needed for removing containers from cartons and cases where side access is unavailable. In such instances each individual container must be engaged from above to be positively lifted from the carton or case and then controllably released, typically on a conveyor system for transport to the next stage of the filling process.
The tops of the containers handled by such apparatus vary considerably, ranging from narrow mouth containers characteristic of soft drink bottles and the like, to wide mouth containers as are now used for products such as peanut butter. Apparatus for handling narrow mouth containers is well known in the prior art, with one example of such equipment being disclosed in U.S. Pat. No. 3,938,847. In the case of wide mouth containers, however, there is insufficient room between containers in a carton or case for a gripper to contract around the outside of the containers, thereby requiring some form of internal gripper in the handling apparatus.
In the prior art, grippers for retaining containers from within have generally been some form of pneumatic apparatus, depending upon the actuation of a pneumatically expandable and contractable bladder in each gripper to provide the gripping and release functions. Such grippers generally operate satisfactorily, though result in certain complexities because of the requirements of a vacuum or pressure source as a prime mover, the connection of each individual gripper on a transport mechanism to the pressure or vacuum source, and the control of the pressure or vacuum source for individual grippers to provide the gripping and release at the appropriate points of progress of the transport system.
One form of mechanical case unloader is disclosed in U.S. Pat. No. 2,609,109. In this unloader a row of internal grippers is mechanically operated in unison by a single operating mechanism, providing substantially positive vertical motion and gripping action as a result of the unitary actuating mechanism. Other grippers, generally relating to nonanalagous arts, are disclosed in U.S. Pat. Nos. 1,504,566; 2,610,082; 2,885,010; 2,491,682; 2,155,620; 3,064,855; and 2,789,859.